74 



Genus Ornithodoros 



tracted at the fourth pair of legs ; border thick, dorsal surface more or 

 less undulating. Integument, both ventrally and dorsally, is beset with 

 posteriorly directed spines or bristly hairs; the spines on the dorsum are 

 much crowded and form a crescentic area anteriorly with concavity 

 directed posteriorly, the horns thereof extending laterally to legs 2 and 3 

 (Neumann) or to legs 3 and 4 (Salmon and Stiles) ; the rest covered by 

 bristly hairs ; ventrally, the spines extend to or slightly beyond the 



Fig. 107. 



Fig. 108. 



Fig. 107. O. megnini. Unfed. Nymph, ventral aspect. Salmon and Stiles, 1901, 6g. 100. 



17th Ann. Eep. B.A.I., U.S. Dept. Agric. 

 Fig. 108. O. megnini. Capitulum of nymph, ventral aspect. Salmon and Stiles, 1901, 



fig. 99. 17th Ann. Eep. B.A.I., U.S. Dept. Agric. 



anus ; integument finely striated, pits absent. Colour, unfed, earthy 

 yellow ; replete, violet brown ; when replete, the contours more rounded, 

 integument glossy, the spines more separated owing to stretching of 

 integument between them. Anus very small, slightly broader (110 to 

 120 /x) than long; two long hairs on each external border. Spiracles 

 300 to 350 fi in diameter, on salient tubercles 1 (seen in Fig. 105) near 



1 Wheler (1901) states that in the living specimen he has seen a "pointed organ," 

 protruded and retracted from the apex of the tubercle, and he gives a rough figure of it in 

 Simpson's paper. The structure requires further study. 



